Gingrich had several events in Bakersfield, Simi Valley and Orange County last week, and praised Colbert for his public service and entrepreneurial background.
"[And] on core values, he is dramatically closer to most Americans than his opponent, and I think on all those standards, there's a real opportunity for us," Gingrich said in an interview Sunday. "You might have said a year ago it isn't winnable, but … you start looking at these districts and begin to think … if we win 70 or 80 seats, [Colbert] probably does win."
The 29th Congressional District is trending "solid" Democrat, according to the nonpartisan Cook Political Report, which did not include Schiff's seat among the 87 competitive House races that are toss-ups and too close to call.
Despite then-presidential candidate Barack Obama winning 53% of the popular vote in 2008, Gingrich said high unemployment and an unpopular health-care law is energizing almost every race in the nation.
"It strikes me that it is a great opportunity for us to pull off something very big," he said. "What does Schiff have to show for all the money they threw away on the stimulus? It didn't work."
Schiff still holds an edge financially, according to campaign filing reports. As of June 30, Colbert had more than $93,000 in cash compared with Schiff's $1.34 million. Schiff has spent more than $695,000 through June 30 versus Colbert's $239,369, $150,000 of which Colbert loaned the campaign himself.
Democrats hold almost a 20-point lead in voter registration in the district, according to the California secretary of state's website.
Schiff voted for the health-care law, as well as the 2009 stimulus and recovery bill. Colbert said he would repeal the health-care law and will support policies that are pro-business.
Parke Skelton, a campaign consultant for Schiff, questioned any advantages from Gingrich's endorsement.